644332326 has 16 divisors (see below), whose sum is σ = 1405816128. Its totient is φ = 195252200.

The previous prime is 644332301. The next prime is 644332361. The reversal of 644332326 is 623233446.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4881240 + ... + 4881371.

It is an arithmetic number, because the mean of its divisors is an integer number (87863508).

Almost surely, 2^644332326 is an apocalyptic number.

644332326 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

644332326 is an abundant number, since it is smaller than the sum of its proper divisors (761483802).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644332326 is a wasteful number, since it uses less digits than its factorization.

644332326 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9762627.

The product of its digits is 62208, while the sum is 33.

The square root of 644332326 is about 25383.7019758742. The cubic root of 644332326 is about 863.7140284075.

The spelling of 644332326 in words is "six hundred forty-four million, three hundred thirty-two thousand, three hundred twenty-six".